Canister structure

Abstract

A branch pipe is coupled to a middle portion of an outside-air connection pipe. A fresh-air inlet of the branch pipe opens into the outside air. A check valve is provided in the branch pipe. The check valve restrains air in the outside-air connection pipe from flowing out into the outside air via the branch pipe and allows the outside air to flow into the outside-air connection pipe via the branch pipe when an inside pressure of the outside-air connection pipe decreases to a specified negative pressure. The fresh-air inlet of the branch pipe is positioned at a specified level higher than a fresh-air inlet of the outside-air connection pipe and disposed in a space formed between wheel house panels and a mud guard.

1. A canister structure, comprising:
 a canister body coupled to a fuel tank and an intake system of an internal combustion engine of a vehicle via respective pipes, the canister body being operative to trap fuel vapor which evaporates in the fuel tank and supply the trapped fuel vapor to the intake system of the internal combustion engine; 
 an outside-air connection pipe coupled to the canister body so as to open into an outside air at a fresh-air inlet thereof, the outside-air connection pipe interconnecting the inside of the canister body and the outside air; 
 a branch pipe coupled to a middle portion of said outside-air connection pipe, a fresh-air inlet of the branch pipe opening into the outside air; and 
 a check valve provided in said branch pipe, the check valve being operative to completely prevent air in said outside-air connection pipe from flowing out into the outside air via the branch pipe, by completely closing a passage of the branch pipe, and allow the outside air to flow into the outside-air connection pipe via the branch pipe only when an inside pressure of the outside-air connection pipe decreases to a specified negative pressure, by opening the passage of the branch pipe, 
 wherein said fresh-air inlet of the branch pipe is positioned at a specified level which is higher than said fresh-air inlet of the outside-air connection pipe and disposed in a space which is formed between a vehicle body member to constitute a wheel house of the vehicle and a mud guard to cover the vehicle body member from a side of a vehicle wheel. 
 
     
     
       2. The canister structure of  claim 1 , wherein said canister body is disposed below a vehicle floor, the middle portion of said outside-air connection pipe comprises a projection portion which is configured to extend upward and then downward in said space, an upper portion of the projection portion is positioned at an upper portion in said space and at a specified level which is higher than said fresh-air inlet of the outside-air connection pipe and a canister-body-side end of the outside-air connection pipe, and said branch pipe is coupled to said upper portion of the projection portion of the outside-air connection pipe. 
     
     
       3. The canister structure of  claim 2 , wherein a filter operative to prevent a foreign substance in the outside air from coming into the canister body is provided at a specified portion of the outside-air connection pipe which is located on a side of the canister body from a connecting portion to the branch pipe, the filter being positioned at a specified level which is higher than said fresh-air inlet of the branch pipe. 
     
     
       4. The canister structure of  claim 1 , wherein a T-shape pipe is provided at said middle portion of the outside-air connection pipe, said branch pipe is configured of a branch pipe portion of the T-shaped pipe, and said check valve is installed in the branch pipe portion of the T-shaped pipe. 
     
     
       5. A canister structure, comprising:
 a canister body coupled to a fuel tank and an intake system of an internal combustion engine of a vehicle via respective pipes, the canister body being operative to trap fuel vapor which evaporates in the fuel tank and supply the trapped fuel vapor to the intake system of the internal combustion engine; 
 an outside-air connection pipe coupled to the canister body so as to open into an outside air at a fresh-air inlet thereof, the outside-air connection pipe interconnecting the inside of the canister body and the outside air; 
 a branch pipe coupled to a middle portion of said outside-air connection pipe, a fresh-air inlet of the branch pipe opening into the outside air; and 
 a check valve provided in said branch pipe, the check valve being operative to completely prevent air in said outside-air connection pipe from flowing out into the outside air via the branch pipe, by completely closing a passage of the branch pipe, and allow the outside air to flow into the outside-air connection pipe via the branch pipe only when an inside pressure of the outside-air connection pipe decreases to a specified negative pressure, by opening the passage of the branch pipe, 
 wherein said fresh-air inlet of the branch pipe is positioned at a specified level which is higher than said fresh-air inlet of the outside-air connection pipe, the middle portion of said outside-air connection pipe comprises a projection portion which is configured to extend upward and then downward in said space, an upper portion of the projection portion is positioned at an upper portion in said space and at a specified level which is higher than said fresh-air inlet of the outside-air connection pipe and a canister-body-side end of the outside-air connection pipe, and said branch pipe is coupled to said upper portion of the projection portion of the outside-air connection pipe.